What will this mean? Well, it could mean that any social network would be able to become compatible with Facebook’s proprietary platform. So developers could run their Facebook application across all the networks with minimal tweaking.

That's huge on a couple fronts. First, it represents a shift in Facebook’s strategy. Facebook has been very careful about opening up its walls. They launched Facebook connect, which allows users to share data on third-party sites, but doesn't bring data into the network. And they originally joined Google’s (GOOG) Friend Connect, but then dropped out right away citing privacy concerns. It also means that Facebook is taking OpenSocial, the Google-led coalition of social networks and app developers, head on.

We’re working on an open-source initiative that is meant to help application developers better understand Facebook Platform and more easily build applications, whether it’s by running their own test servers, building tools, or optimizing their applications. As Facebook Platform continues to mature, open-sourcing the infrastructure behind it is a natural step so developers can build richer social applications and share what they’ve learned with the ecosystem. Additional details will be released soon.